Be carefull of any liquid heated in microwaves. (this mostly applies to boiling liquids) Microwaves tend to heat liquids in layers, often causing a cooler layer under a hot layer, under another cooler layer. When the vessel is moved, or worse, tipped to take a drink, the layers mix and often "overboil" or seem to "explode out of the cup". Many people have suffered 3rd degree burns from this.
Originally Posted by gainer
It's likely that this will not apply to gainer's method as the temps involved are lower, but it is good to know if you zap your luke warm drink.
Stir first, then move and drink.