Self Diagnostic Emergency Light time delay after a power outage

So I was shopping at Costco, and a few minutes later the power went, and these units turned on and after three minutes the power went on, and it went off again. After the power outage (which I'm assuming that they're testing the electrical safety equipment) these units were on still, and the green LED on the unit of the self diagnostic display is on, which means these have a time delay, just like the Dual-Lite ones.

After a power outage, these have a time delay on the lamp heads, IDK how long they stay on at time delay. Oh BTW, these have halogen heads.