Dichloromethane and toluene are solvents. They do not convert into carbon monoxide through any sort of reaction in your body. They are used as solvents for chemical reactions, diluting and cleaning organic hydrophobic residues and are much more likely to make you grossly sick and cause long term tissue or organ damage than kill you as a way of committing suicide. These things are actually difficult to metabolize. When organic chemists do reactions to make different organic molecules they often choose solvents that dissolve the reagents but do not interact with them. Things like toluene whcih is a 6 membered ring is a common non polar solvent chosen primarily because it is much less carcinogenic than it's cousin benzene. Both can be toxic to a human but only over long exposure. I could see a human drinking the stuff but then having some very strange and painful organ processes in the GI, liver and kidneys that you could very likely survive and then have long term damage. Dichloromethane which is a close cousin of trichloromethane or carbon tetrachloride is an organic solvent that has the big "fuzzy" electron clouds of the clorine molecules that can take up the polar charge during a reaction. But these thing all have one common thing associated with them, they are inert.
Rapid death to a human typically depends on such methods as exanguination (blood loss), blunt force trauma, stopping the heart which stops processes that keep the brain tissue and organ tissue doing their things, or stopping the respiration processes.
From a chemical perspective toxic, meaning acute toxic depends on interfering with those processes. In WWI and WWII chlorine and phosgene gas were used to kill troops quickly as chemicals. The chlorine gas and phosgene are super reactive (unlike the solvents in paint thinner) and caused hirrible, painful,gruesome damage to respiratory tissue leading to hospitalization and typically death by pulmonary edema (your lungs fill up with fluid from burst blood vessels and you die)
Getting back to paint thinner. Yes they are toxic but so is gasoline. You can die from drinking them but it's a death that is not guaranteed, not quick and not caused by the type of fast acting death that inhibited respiratory or cardiac tissue would cause. A large amount of the solvent which would not metabolize or soak into tissue would pass through the GI tract but not be hit by the bacteria in your gut so it would cause severe cramping and diarrhea. The solvent that did uptake would cause your kidneys and liver to shift into overdrive trying to take it out of your blood. They might go into renal failure or liver failure. They also might be damaged beyond repair but instead of dying you could simply be on dialysis for the future.
If we look at toxicity that relates to fast death then the key components are those things that either clog up the transport of oxygen preventing the flow of that vital molecule to nerve and muscle tissue, or stops the automated neurological firing of the hard wired neurons that keep your heart and lungs doing their thing at all times.
Killinng off your kidneys, liver or other organs is a way to die but one can live a long and painful time with those severely damaged.
I truly don't recommend that anyone drink any solvents, cleaning products or things that are designed to caustically tear apart other things like paint. Your digestive system is delicate and there is a reason why middle age torturers focused on damaging that set of organs to keep their victims alive in gruesome barbaric practices; you can live a long time with damaged organs that are not your heart, lungs, circulatory system or brain.
