Okay, that sounds good. The hot water for 30 seconds or so really warms up the rat to get BP's heat pits excited! Even if it is defrosted and at room temp, no problem. Some people use a hairdryer, but I do not think it does as uniform job.
You can dry a wet rat with just paper towels.
Does not hurt anything for the rat to get wet when defrosting.
The snakes seem to prefer a drier rat, but many do not care. The bigger issue, as addressed, is a wet rat can get substrate stuck to it.