diff --git a/03-DESIGN/01-to-be/04-lab-installation.md b/03-DESIGN/01-to-be/04-lab-installation.md
index 5c4944e..2d00788 100644
--- a/03-DESIGN/01-to-be/04-lab-installation.md
+++ b/03-DESIGN/01-to-be/04-lab-installation.md
@@ -48,6 +48,7 @@ present, but that the machine can actually do the work:
 | **the pool the lab will use is on that driver** | a pool exists, and is the slow kind — the failure that has no symptom |
 | hardware virtualisation is present | machines will be emulated and unusably slow |
 | an image can be fetched or is cached | the first raise will fail late instead of early |
+| **a machine on an uplink reaches something real**, by fetching it — not by reading a route or a policy | forwarding is being dropped by something else on the workstation; names still resolve, and every pull hangs |
 
 Each check states **why it matters**, in the terms of what it costs. *"The pool uses the `dir`
 driver"* means nothing to someone who does not already know it means seventy-six times slower