To get to Isetan, exit the station ticket gates and head towards the North Exit (Lumine/Bic Camera) through the concourse, then walk along the pedestrian deck towards the large vision screen.
You should see Isetan, and if you enter directly from the deck, you'll find a resting area near the main entrance where you can sit.
Benches that can accommodate about 20 people are set up around the entrance and exit.
These benches have long been popular with the elderly, and many people use them for taking a break from shopping or meeting up with someone.
It's convenient when you want to take a break after navigating through the crowded deck.
Please note that since it's near the entrance and exit, the air conditioning isn't very effective.
But don't worry!
There's a "bench next to the escalator at Tachikawa Isetan" nearby.
Consider that option as well!
Also, please note that the business hours are from 10:00 to 19:00.
Why not use this spot for a break while shopping at Isetan or as a resting place near Tachikawa Station?