Rek'sai's Tunnel Not Breakable But Still Usable? [Gameplay]

When my friends and I played league, we were up against a Rek'sai top. 1.Rek'sai made a tunnel, we believed we stopped him while she was going through the tunnel half way (as seen in the picture) 2. We tried to break the tunnel but there was no white bar on the tunnel and it won't break. 3. Rek'sai could still use the tunnel and ult to the tunnel. Thats all that happened, #RiotPlzFix!