My observations for what they're worth (No speculation or judgement)
I watched the a/c make a normal landing on 10 pleased to see it on time as I was due to travel on its next rotation to PMI. Nothing out of the ordinary going on, outbound crew were in the dep lounge awaiting its arrival on stand.
The drama unfolded out of sight, view being hidden by the twr. From the pictures I've seen the a/c was obviously well into the backtrack (cleaned up) at the point it stopped and subsequent evacuation took place.
After some time an airfield ops vehicle was noted escorting two off airport fire engines onto 10. Same again with an ambulance a few minutes later. It was only when I saw the tug and towbar followed by Jet2 engineers van trundling across the apron in an easterly direction that the old grey matter started to ponder.
A/c was eventually towed onto stand where used chutes were dumped on apron . Snippets of conversation overheard suggesting runway closed due to hydraulic fluid contamination. More than two hours after the event a quad bike with tanks on rear akin to something used by the council for kerbside weedkilling was escorted to the runway, I guess for the big clean up!
Reassuring to read SK's ramblings in the Gazette that BLK emergency procedures kicked in and worked (right down to the double deck school bus which finally brought the inbound pax to the tent in two runs)
On boarding the replacement a/c LS positioned over from LBA, I noted LJ jacked with R/H MLG inboard wheel removed. Jet2 (other than a rather quiet set of ground staff) handled it well. BLK handled it like BLK do.
As I said, just my observations.