What would happen if I poured enzymes into a glass filled with ATP?

What makes you think logic will dictate that the reaction will be rapid?

Concentration / rate of reaction
The bombardier beetle uses the same principle, high concentration of enzymes meeting a high concentration of the substrates they break down (it produces a reaction that meets nearly the boiling point of water)

True. Here's a breakdown from Wikipedia:

The spray is produced from a reaction between two chemical compounds, hydroquinone and hydrogen peroxide, which are stored in two reservoirs in the beetle's abdomen. When the aqueous solution of hydroquinones and hydrogen peroxide reaches the vestibule, catalysts facilitate the decomposition of the hydrogen peroxide and the oxidation of the hydroquinone. Heat from the reaction brings the mixture to near the boiling point of water and produces gas that drives the ejection.

So, correct me if I'm wrong, two separate chemicals are made. Once they mix, heat is released.

The 'catalysts' are enzymes. Mostly catalase which decomposes the HP and the decomposition creates heat.

I see. I doesn't burn itself, apparently due to split-second pauses in-between bursts (firing between 368 and 735 pulses per second) which allows it to cool down.