What happens to Tyrell in the woods?

Tyrell is dead, he died alone in the woods.

This article from the Hollywood Reporter features quotes from both Sam Esmail and Martin Wallström explaining their thoughts on it. I've added a short excerpt below but the whole article is a bit too long to quote.

Moments after the epiphany, Elliot and Tyrell come across the Dark Army operative, who kills himself, but not before fatally shooting Tyrell. Recognizing his own impending demise and the ramifications of what happens if his body is discovered by the Dark Army, Tyrell chooses to walk back into the woods to die alone, buying Elliot some time in his quest against Whiterose (BD Wong). The episode ends with Tyrell stumbling toward a glowing blue light, before the scene fades to white.

From the outside looking in, Tyrell's death comes as a shock on a few different levels. For one, it's only a quarter of the way into the final season; Tyrell has been a central figure in the Mr. Robot mythos from the very beginning, even earning the iconic penultimate line of the pilot: "Bonsoir, Elliot." For another, Tyrell dies just as he was about to be named the new CEO of E Corp — literally, dying one day short of the coveted appointment. But as Esmail explains to THR, Tyrell's inopportune demise was right for the same reason he felt it necessary to kill off Angela: "The story told us when it was time."