1) 70% ethanol evapourates at 50oC (or there abouts), therefor you shouldn't use it to wipe up spilt stuff on a heating block while it's nice and toasty
2) ethanol is more readily absorbed through the membranes lining the nasal passages than the lining of the stomach, therefore it will enter the bloodstream much faster when inhaled as a vapour
3) it is hard to notice that you are under the influence of inhaled alcohol fumes, because the familiar warm and toasty feeling in the stomach which normally accompanies alcohol com\nsumption is missing
4) working in a lab while mildly intoxicated is somewhat amusing, though probably a bad thing
... anyway, these rules are by no means related. I swear. I just got out of the lab for a coffee, not to give my liver a chance to do it's stuff...